MILWAUKEE -- Newt Gingrich is calling on federal officials to overhaul the nation's prison system, an issue he knows isn't a typical Republican hot-button topic.

The former House speaker made his comments during a brief stop in Milwaukee on Monday evening at a fundraiser for gubernatorial candidate Scott Walker.

Gingrich said nonviolent offenders should be given a real chance to rehabilitate, in a prison system that doesn't expose them to gang turf wars and threats of rape.

He said the U.S. shouldn't tolerate barbarism inside walls it theoretically controls.

Gingrich's comments were met with polite applause by the crowd of GOP supporters.

Gingrich attended on behalf of Milwaukee County Executive Scott Walker, who's running for governor in 2010. Gingrich praised Walker but stopped short of a full endorsement.

Walker ran for governor in 2006 but dropped out as his fundraising lagged. He's running again in the 2010 election, where he'll face Appleton businessman Mark Todd. Former U.S. Rep. Mark Neumann is also expected to enter the race.

The Gingrich fundraiser in Milwaukee comes at the end of a six-month reporting period for campaign donations that is critical for candidates to show their ability to raise money